Digestive System

• Mouth
• Removes harmful substances from the blood
• Liver
• Esophagus
• Saliva

Questions:

• The digestive process starts in the?
• What does the liver do?
• Bile is made in the?
• What tube moves the food from the back of your throat to the stomach?
• When you chew food what is squirted into your mouth?

partoid:

• largest gland
• produce a serous, watery secretion.

The Digestive System

• sublingual gland

The Oral Cavity's Function

submandibular gland:

• The secretion is a mixture serous and mucous

submandibular gland: located under the tongue; The secretion is a mixture of serous and mucous.

Produces 70% of all saliva, even though it is much smaller than the parotid gland.

Salivary Glands

• The teeth mash up the food.
• The tongue mixes the chewed food with saliva.
• During swallowing, the tongue pushes the food to the back of the throat, into the pharynx.

• The presence of food triggers a nervous reflex that causes the salivary glands to deliver saliva through some ducts and into the mouth.
• Saliva helps with the breaking down of the food.
• Three types of salivary glands:
• partoid
• submandibular
• sublingual

The Oral Cavity Structure

The oral cavity consists of:

• teeth
• tongue
• salivary glands
• palate

Santiago Z.

Philipp R.

Pharynx Function

Pharynx Structure

• A juncture that opens to both the esophagus and trachea.
• Fibromuscular tube that extends from the base of the skull to the esophagus.

• Swallowing takes place here.
• It closes off the trachea so that food does not fall into it and choke you.

Sources

Esophagus Structure

Esophagus Function

Disorders and Diseases

• It is the passage for food to travel to the stomach with help of the:
• Peristalsis: a series of wavelike muscle contractions that propel food in one direction.

• A muscular tube extending from the pharynx and behind the trachea to the stomach.
• Before the opening to the stomach, there is an important ring-shaped muscle called the lower esophageal sphincter (LES).

• Barrett's Esophagus: Normal cell structures in the Esophagus are replaced by simple goblet cells (Secrete huge amounts of mucus). (Surgey and Radiofrequency ablation).
• Esophageal cancer (adenocarcinoma) (85%)
• GERD
• Gastroesophageal reflex disease:
• Acidic stomach contents back up into the esophagus, causing irritation and heartburn (Surgery and Medication).
• Western world

10 and 20% of the population is affected

Liver Structure

Function

Fat Emulsification : breaking up fats to

increase surface area

Bile Production

• Bile: yellow-green alkaline solution that consists of:
• water
• bile salts
• bile acids
• phospholipids
• cholesterol
• pigments
• electrolytes

• Metabolizes toxic substances.
• Removes/stores iron and vitamins.
• Produces proteins in blood plasma.
• Controls cholesterol levels.
• Stores glucose as glycogen.
• Breaks down glycogen and releases ammonia as a byproduct.

• Jowett, Shrestha, 1998. Mucosa and taste buds of the human epiglottis. Journal of Anatomy 193(Pt 4): 617–618 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1467887/
• Newton, W. (1837). "The invention of certain improvements in the manufacture of soap, which will be particularly applicable to the felting of woollen cloths.". The London Journal Of Arts And Sciences; And Repertory Of Patent Inventions IX: 289. Checked 2014-05-10. http://www.google.co.uk/books?vid=0MfyvmoTsdK02ZeP86W&id=GhMAAAAAMAAJ&pg=RA19-PA291&lpg=RA19-PA291&dq=bile+soap&as_brr=1#v=onepage&q=bile%20soap&f=false
• Smithuis, Robin. "Anatomy of the liver segments". Radiology Assistant.Checked 2014-05-10 http://www.radiologyassistant.nl/en/p4375bb8dc241d/anatomy-of-the-liver-segments.html
• Guillaume, Jean; Praxis Publishing, Sadasivam Kaushik, Pierre Bergot, Robert Metailler (2001). Nutrition and Feeding of Fish and Crustaceans
• "New Research Redraws Pancreas Anatomy". Checked 2014-05-10 http://medicalxpress.com/news/2011-07-redraws-pancreas-anatomy.html
• McBroom, A. J.; Kuehn, M. J. (2007). "Release of outer membrane vesicles by Gram-negative bacteria is a novel envelope stress response http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1868505/
• http://en.wikipedia.org/wiki/Main_Page
• https://www.google.com.mx/?gfe_rd=cr&ei=eXFuU8nPKsqS8Qf0jYD4Ag
• https://sketchfab.com/models/0ec73121e6734880a8de5cdf0ce1db7e

Stomach :

Disorders and Diseases

• Storage.
• Mechanical breakdown of ingested food and chemical bonds through enzymes and acids.
• Production of Intrinsic Factor necessary for absorption of B12.

• Hepatitis: inflammation, commonly caused by viruses, transmitted via
• (A) contaminated food/water
• (B) sexual contact
• (C) contact with infected blood
• Cancer,Alcohol Damage, Drug Damage
• Cirrhosis: Fatty tissue replaced by scar tissue

• Rest (A,E)
• Medication (B,C)(Might be needed in all of them)
• B,C,D might need liver transplant

Structure:

Four Main Regions

Body

Cardia

Includes:

Chemical

The opening of the esophagus into the stomach.

destroys bacteria and alters pH levels.

Hydrochloric Acid:

enzymes that break down ingested food.

Proteases:

(LES):

one way valve connects from esophagus

to the stomach.

Physical

Muscularis externa:

smooth muscle that contracts in wall of stomach.

Heartburn:

(LES) does not tighten enough or opens too often.

• Churns (Mixes) food, acid, and enzyme.

Fundus

Pylorus

• Prevent intestinal content from reentering the stomach when the small intestine contracts.
• Limits the passage of large particles or undigested material to enter the intestine.

Main job is to expand and make room for more food.

Made out of:

Parietal cells:

produces Hydrochloric acids and intrinsic factor.

produces pepsin and lipase.

Chief cells:

produces mucus.

Mucus cells:

Gallbladder Structure

Disorders and Diseases

Gallbladder Function

• Removes water and ions from bile for higher concentration.
• When not digesting, pancreatic obiliary sphincter closes to block bile access to the duodenum.

• Cholesterol content of bile can crystallize into gallstones that blocks the passageway to the small intestine
• Leads to
• indigestion, infection, pain, nausea, vomiting
• Jaundice: yellowing of skin
• Liver damage

Most common way to treat : surgical Removal

Diseases

Cancer:

Very rare and usually happens because acid levels are inconsistent.

Diarrhea:

Bacteria and viruses increase the amount of liquid

secreted in the stomach and makes it flow too quickly.

Gastritis:

-Food remains inactive in stomach.

- If no soon treatment, then blood will

start to leak and vomiting blood can

begin to happen.

Structure of Pancreas

Function of Pancreas

Diseases & Disorder of Pancreas

• Pancreatic Cancer
• Lack of insulin production can lead to Diabetes Mellitus
• Type I: Metabolizes fat instead of glucose, increases blood acidity
• Type II: Adipose tissue impairs insulin receptors, insulin resistant cells

• Produces digestive enzymes for the small intestine
• Produces vasoactive intestinal polypeptide (VIP) (Hormone)
• relaxes gastrointestinal tract
• triggers hormone release from pancreas
• breaks down fat and glycogen
• stimulates bile flow
• Hormone Somatostatin: Limits and controls insulin and glucogen production.

Medical treatment and therapy

Small Intestine

Function of Small Intestine

Overall

• Finishes the process of chemical digestion
• Breaks down food using enzymes released

from the pancreas and bile from the liver.

• Absorbs nutrients

Parts

• Duodenum
• Jejunum & Ileum

Large intestine

• Absorbs H20, salts and some vitamins
• Stores undigested material until it is eliminated as feces

Each part:

• Cecum
• Colon
• Rectum

Structure & Function of Appendix

Appendix

• Storage of healthy bacteria to replace bacteria purged after dysentery (Inflammation of the colon)
• Removal of appendix has no adverse affects